1. Field of the Invention
The present invention relates to process control operator workstations in general and more particularly to such workstations that are ergonomically designed to provide adjustability accommodating a range of human operator dimensions from females in the 5th percentile up to males in the 95th percentile.
2. Description of the Prior Art
The science of ergonomics deals with the design of equipment and tools so as to make the equipment and tools easily used by the human operator without undue fatigue. The ease of such use as well as the minimizing of strain and fatigue involves designing the tool and equipment to maintain proper orientation with the human operator. As is readily apparent, the "human operator" is a extremely variable entity and different individuals have varying height, reach, angular movement, and differ in various other dimensions all of which must be considered in the proper design of the equipment that the operator will use or interface. This variation of human operators has been outlined in tables created by THE HUMAN FACTORS SOCIETY INC. which variations are summarized in the table of FIG. 1. In this particular table, various anthropometric data are provided which represents the U.S. civilian body dimension for ages 20 to 60 years as determined by J. T. McConville of Yellow Springs, Ohio in his Anthropology Research Project and by K. W. Kennedy in his USAF-AMRL-HEG paper presented in 1985. The later paper is based on military data excerpted from the McConville Research Project of 1978.
Turning specifically to operator workstations and their consoles of the type used in process control rooms, the application of ergonomic design consisted, for the most part, of an attempt to provide compatibility of the console with an operator of normal or average anthropometric values. Adjustability of the video display screens consisted usually of making the screen tiltable to provide a good orientation of the video screen to the face of the operator. The dimensioning of the operator's height with respect to the console retaining the screen, for the most part, consisted of a chair being vertically and rotationally adjustable. These adjustments, although providing a certain modicum of compatibility of the operator to the workstation, left out certain other key factors dealing with the fatigue of the operator such as proper angle of the legs with respect to the buttocks in the seated position as well as the angular orientation of the wrist with respect to the keyboard.
Another problem in operator workstation interfaces involved the poor or inadequate location of various status displays and actuators that may have to be operator actuated in response to conditions viewed on the monitor screen by the operator while inputting or monitoring process control data. Process control operators may need to react as quickly as possible to certain adverse conditions during start-up and loading of setpoints and data into critically controlled systems such as nuclear reactors or gasoline refineries. An alarm condition has to be quickly if not instantaneously acted upon. Prior art location of such actuators was usually somewhat removed from the video monitor and even when in relatively close proximity thereto, provided a poor viewing angle for the operator preventing him from simultaneously viewing both the monitor and the actuator board.
Thus, the prior art did not meet the needs of the process control industry for a true ergonomically designed operator workstation consisting of consoles that are adjustable to accommodate human operators ranging from the 5th percentile female to the 95th percentile male. Furthermore, process control workstations were needed wherein the actuator keyboard would be in immediate proximity to the video monitor and would be adjustable to provide the simultaneous viewing of both the monitor and the actuator board by the mentioned range of human operators.